Liebert AC4 Connecting Digital Inputs and Outputs, Connecting Liebert Environmental Units

Wiring and Connections

3.2Connecting Digital Inputs and Outputs

The digital inputs and outputs are found on the lower right side of the AC4’s printed wiring assembly board. This section describes how to connect devices to the AC4’s inputs and outputs.

Each input is tied to an output with the same number:

•Input 1 is tied to Output 1 (default name: Device_1)

•Input 2 is tied to Output 2 (default name: Device_2)

•Input 3 is tied to Output 3 (default name: Device_3)

•Input 4 is tied to Output 4 (default name: Device_4)

Up to four devices may be connected to the AC4. Each device must be connected to an input and an output with the same number.

To determine the proper wire size, see Table 4 - Wiring specifications.

NOTE

Each terminal block is a removable assembly to permit easier connection of more than one input or output at a time. If making multiple connections, grasp the upper portion of a block and pull firmly until the assembly pulls apart.

After making the connections, push the removed piece back into the portion attached to the printed wiring assembly until the terminal block pieces lock together.

Connecting Liebert Environmental Units

For Liebert environmental units, follow these steps (be sure to connect the same device to inputs and outputs with the same number (Input 1 and Output 1, Input 2 and Output 2, and so on):

•Connect a digital input from the AC4 to the Common Alarm Relay of the environmental unit: terminals 75/76 or TB1-6,TB1-7.

•Connect a digital output (numbered the same as the input) from the AC4 to the Remote Shutdown (Power Control) of the environmental unit: terminal 37/38 or TB1-4, TB1-5.

3.2.1	Connecting Digital Inputs	OUTPUT TERMINAL
	The four digital inputs are found on the lower right side of	BLOCKS
	the AC4 just below the output terminal blocks, as shown at	Note numbering keys
	right. These inputs are numbered 1 through 4.	to right of terminal
		blocks; outputs are
	To connect an input:	numbered from
	1. Turn OFF electrical power to the AC4.	bottom (1) to top (4)
	2. If necessary, remove a conduit knockout to permit wire
	entry into the AC4 enclosure.
	3. Bring the wire(s) into the AC4 enclosure through a		Numbering
	conduit knockout or access slot.
			keys
	4. Loosen the appropriate screw and slip the stripped end
	of the wire into the terminal block.
	5. Tighten the screw until it holds the wire snugly.	INPUT TERMINAL
3.2.2	Connecting Digital Outputs	BLOCKS
		Note numbering keys
	The four digital outputs are found on the lower right side of	to right of terminal
		blocks; inputs are
	the AC4 just above the input terminal blocks, as shown at
		numbered from
	right. These outputs are numbered 1 through 4.
		bottom (1) to top (4)
	To connect an output:

1.Turn OFF electrical power to the AC4.

2.If necessary, remove a conduit knockout to permit wire entry into the AC4 enclosure.

3.Bring the wire(s) into the AC4 enclosure through a conduit knockout or access slot.

4.Loosen the appropriate screw and slip the stripped end of the wire into the terminal block.

5.Tighten the screw until it holds the wire snugly.

! CAUTION

To reduce the risk of fire or electric shock, do not interconnect the outputs of different class 2 circuits.

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